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Table 3 Overview of diaphragm motion during the breathing control strategies under investigation

From: Quantifying the reduction of respiratory motion by mechanical ventilation with MRI for radiotherapy

Median (range) values

MRI1

MRI2

N

p-value

Testing differences between MRI sessions

DIBH IQR (mm)

5.4 (1.2–14.9)

4.0 (1.0–23.6)

14

0.221

FB amplitude (mm)

20.2 (10.6–31.9)

22.1 (12.8–41.9)

14

0.362

RB amplitude (mm)

11.3 (6.2–20.3)

16.6 (9.3–23.8)

14

0.024

PIBH drift (mm/minute)

3.0 (0.4–6.5)

2.7 ( 0.9–6.0)

15

0.125

PEBH drift (mm/minute)

4.9 (2.2–7.9)

3.8 (1.8–15.1)

14

0.064

Median (range) values

FB

RB

N

p-value

Testing differences between breathing control strategies

MRI1 amplitude (mm)

20.2 (10.6–31.9)

11.3 (6.2–20.3)

14

< 0.001

MRI2 amplitude (mm)

22.1 (12.8–41.9)

16.6 (9.3–23.8)

14

0.002

MRI1 & MRI2 amplitude (mm)

20.9 (10.6–41.9)

12.8 (6.2–23.8)

28

< 0.001

Median (range) values

PIBH

PEBH

N

p-value

Testing differences between breathing control strategies

MRI1 drift (mm/minute)

3.0 (0.4–6.5)

4.9 (2.2–7.9)

14

0.002

MRI2 drift (mm/minute)

2.7 ( 0.9–6.0)

3.8 (1.8–15.1)

15

0.001

MRI1 & MRI2 drift (mm/minute)

3.0 (0.4–6.5)

4.4 (1.8–15.1)

29

< 0.001

  1. Bold values indicate the significant p-values
  2. For deep inspiration breath-holds (DIBHs), diaphragm motion is expressed by the inter-quartile range (IQR) of the consecutive breath-holds. For free breathing (FB) and regularized breathing (RB) at 22 breaths per minute the diaphragm motion is quantified by the breathing motion amplitude measured on 4DMRIs. For prolonged breath-hold from inhalation (PIBH) and exhalation (PEBH), diaphragm motion is expressed in the diaphragm drift velocity. Due to missing data and unsuccessful reconstructions, the number of pairs to be compared (N) per test varies. Significance was tested with a Wilcoxon signed-rank test (α = 0.05). P-value is shown in boldface when the difference was significant